Phototypesetting machines are generally complex, expensive units requiring highly skilled operators to accomplish a number of complicated procedures during a typesetting operation. Such machines often employ computers or special circuit cards to provide character width information and other control information. Often a number of separate typefonts must be selected and the proper machine settings or circuit cards chosen for each font. An error in any of the numerous steps required to set up and subsequently operate such machines is likely to result in an abortive typesetting operation.
A tremendous need has arisen for a simple, inexpensive phototypesetting machine that may be operated by anyone having normal typing skills. Such a machine would make phototypesetting available to schools, small businesses, small trade journals and newspapers, and other organizations to which phototypesetting has previously been denied by the price and complexity of the equipment.
Applicant has designed a very simple, compact and inexpensive typesetting machine which employs a novel rotating disc typefont. Basically, phototypesetting machines employing rotating disc typefonts are very well known in the art. A number of early patents to Rene Higgonnet and Louis Moyroud disclose phototypesetting machines using rotating disc typefonts which are driven between flashlamp and lens assemblies. The flashlamp and typefont may be mounted on a carriage which moves relative to a photosensitive receiving medium and the photosensitive receiving medium is then driven in a direction normal to the direction of carriage movement. These known phototypesetting machines generally employ a disc typefont having characters arranged in a circle spaced from the center of the font. These characters are located by means of a circular arrangement of timing marks with one mark being provided for each character.
Disc typefonts have been developed which bear a plurality of different alphabets or character groups, but invariably, these alphabets are arranged in concentric circles on a unitary font. A problem arises when it becomes desirable to employ one or two alphabets on a font in combination with a plurality of third alphebets, for this requires the frequent substitution of a plurality of discs. Generally separate character width information must be preset in some manner for each disc used, thereby rendering the operation quite complex. In the past, some attempts, have been made to code width information on a disc typefont, but since the font is rotating at a high speed, effective coding has been difficult. For example, U.S. Pat. No. 3,695,155 to Hans Guldenpfenning discloses a disc typefont for a phototypesetting machine which includes a width slot for each character. However to sense width from such width slot, it is necessary to stop the rotation of the disc and scan the width slot while the disc is stationary. This is an extremely slow process.
It is a primary object of the present invention to provide a novel and improved phototypesetting machine which is compact, simple to operate and inexpensive.
It is another object of this invention to provide a novel and improved phototypesetting machine incorporating a rotating disc typefont which facilitates the mixing of a plurality of alphabets or different character groups and directly provides size and width information to the machine without requiring operator selection.
A further object of the present invention is to provide a novel and improved phototypesetting machine incorporating a rotating disc typefont having character timing marks and a width code on the font; such machine being adapted to employ the timing marks and width code to derive width information from the font as the font rotates at high speed.
A still further object of the present invention is to provide a novel and improved phototypesetting machine incorporating a rotating disc typefont having removable sectors and a novel mounting assembly for such typefont.